Endothelial cells are mesodermally derived, simple squamous epithelial cells that line the heart, blood and lymph vessels, line any closed cavity (peritoneal, pleural, pericardial, synovial) and line the intestinal tract. Endothelial cells of blood vessels have both mechanical and functional properties. They provide a barrier effect to the penetration of blood components into the vessel wall and have endocrine functions.
Vascular endothelium is a multi-functional barrier separating blood from interstitium. It plays a role in coagulation, inflammation, angiogenesis and has vasomotor functions. Endothelial dysfunction can be considered as an initial stage of atherosclerosis. Malik J, Melenovsky V, Wichterle D, Function and dysfunction of the endothelium, Cas Lek Cesk 2000 Apr. 12; 139(7):197-202. Endothelium dysfunction is recognized as an early event in the pathogenesis of cardiovascular disease, and linked to hypertension, diabetes mellitus and oxidative stress. Pepine C J, Clinical implications of endothelial dysfunction, Clin Cardiol 1998 November; 21(11):795-9.
Endothelial dysfunction is characterized by a loss of barrier function and an infiltration of cellular material into the vascular wall and loss of physiological vascular tone. There is a loss of nitric oxide mediated physiological vasodilation, increased endothelial adhesion and migration of leucocytes and macrophages into the subendothelial vascular wall. Hypoxia, shear forces and oxidative stress trigger events for endothelial dysfunction. Disorders associated with endothelial dysfunction may occur in any endothelial cells and include; hypertension, atherosclerosis, diabetes, immune system dysfunction, infections, inflammations, macular degeneration, cardiovascular disease and stroke.